# CVE-2026-71217: Iperf3: iperf3 server accepts unbounded peer-controlled json parameters enabling remote denial of service via resource exhaustion CVE-2026-71217 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-71217, released August 11, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-71217 - Priority: High - CVSS: 7.5 (Important) - EPSS: 0.0064 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 11, 2026 - Weakness: Improper Input Validation - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-71217 ## Description A flaw was found in iperf3. A remote attacker can exploit this vulnerability by sending crafted control-channel JSON with oversized numeric parameters, such as `parallel` and `len`, which are not properly validated by the server. This improper input validation can lead to excessive stream and thread creation, as well as large buffer allocations, causing resource exhaustion. Consequently, this can result in a Denial of Service (DoS) on the affected iperf3 server. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | iperf opensuse-leap 16.0 | 3.21-160000.1.1 | [OPENSUSE-SU-2026:22090-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22090-1.md) | Nov 7, 2026 | | Linux | iperf sles 15.7 | 3.22-150000.3.18.1 | [SUSE-SU-2026:4678-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4678-1.md) | Nov 7, 2026 | | Linux | iperf sles 16.0 | 3.21-160000.1.1 | [SUSE-SU-2026:24234-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24234-1.md) | Nov 7, 2026 | | Linux | iperf3 Debian 14 | 3.22-0.1 | [DEBIAN-CVE-2026-71217](https://patchblox.com/security/data/fix/linux/debian-cve-2026-71217.md) | Aug 11, 2026 | | Linux | iperf3 RHEL 10 | 3.17.1-6.el10_2.1 | [RHSA-2026:61680](https://patchblox.com/security/data/fix/linux/rhsa-2026-61680.md) | Sep 2, 2026 | | Linux | iperf3 RHEL 8 | 0:3.5-12.el8_10.1 | [RHSA-2026:61257](https://patchblox.com/security/data/fix/linux/rhsa-2026-61257.md) | Sep 13, 2026 | | Linux | iperf3 RHEL 9 | 0:3.9-17.el9_8.1 | [RHSA-2026:61389](https://patchblox.com/security/data/fix/linux/rhsa-2026-61389.md) | Sep 13, 2026 | | Linux | iperf3 almalinux 10 | 3.17.1-6.el10_2.1 | [ALSA-2026:61680](https://patchblox.com/security/data/fix/linux/alsa-2026-61680.md) | Aug 31, 2026 | | Linux | iperf3 almalinux 8 | 3.5-12.el8_10.1 | [ALSA-2026:61257](https://patchblox.com/security/data/fix/linux/alsa-2026-61257.md) | Aug 31, 2026 | | Linux | iperf3 almalinux 9 | 3.9-17.el9_8.1 | [ALSA-2026:61389](https://patchblox.com/security/data/fix/linux/alsa-2026-61389.md) | Aug 31, 2026 | | Linux | iperf3 amzn 2023 | 3.19.1-1.amzn2023.0.1 | [ALAS2023-2026-2070](https://patchblox.com/security/data/fix/linux/alas2023-2026-2070.md) | Aug 31, 2026 | | Linux | iperf3 ol 10 | 0:3.17.1-6.el10_2.1 | [ELSA-2026-61680-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61680-0.md) | Sep 1, 2026 | | Linux | iperf3 ol 8 | 0:3.5-12.el8_10.1 | [ELSA-2026-61257-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61257-0.md) | Sep 1, 2026 | | Linux | iperf3 ol 9 | 0:3.9-17.el9_8.1 | [ELSA-2026-61389-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61389-0.md) | Sep 1, 2026 | | Linux | iperf3 rocky 10 | 0:3.17.1-6.el10_2.1 | [RLSA-2026:61680](https://patchblox.com/security/data/fix/linux/rlsa-2026-61680.md) | Sep 1, 2026 | | Linux | iperf3 rocky 8 | 0:3.5-12.el8_10.1 | [RLSA-2026:61257](https://patchblox.com/security/data/fix/linux/rlsa-2026-61257.md) | Aug 31, 2026 | | Linux | iperf3 rocky 9 | 0:3.9-17.el9_8.1 | [RLSA-2026:61389](https://patchblox.com/security/data/fix/linux/rlsa-2026-61389.md) | Sep 1, 2026 | | Linux | iperf3-debuginfo amzn 2023 | 3.19.1-1.amzn2023.0.1 | [ALAS2023-2026-2070](https://patchblox.com/security/data/fix/linux/alas2023-2026-2070.md) | Aug 31, 2026 | | Linux | iperf3-debugsource amzn 2023 | 3.19.1-1.amzn2023.0.1 | [ALAS2023-2026-2070](https://patchblox.com/security/data/fix/linux/alas2023-2026-2070.md) | Aug 31, 2026 | | Linux | iperf3-devel amzn 2023 | 3.19.1-1.amzn2023.0.1 | [ALAS2023-2026-2070](https://patchblox.com/security/data/fix/linux/alas2023-2026-2070.md) | Aug 31, 2026 | --- Data as of 2026-11-09T01:18:40Z UTC. 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